Valve for vacuum installation

ABSTRACT

The invention relates to valves for vacuum installations wherein the closing element is connected with the movable part of the drive which can be fixed in the &#39;&#39;&#39;&#39;open&#39;&#39;&#39;&#39; and &#39;&#39;&#39;&#39;closed&#39;&#39;&#39;&#39; positions and can move freely between these positions. The claimed drive comprises a bushing having side projections and installed with their aid in linear guides of the valve body for moving in them without turning towards a seat 16 and away from it with the aid of at least one two-arm lever connected with said bushing and bearing with one end against the body of said valve when the latter is opened. The length of the linear guides is approximately equal to the length of the free travel of said bushing, and the side projections of said bushing and said body of said valve have flats slanted at one and the same acute angle to the longitudinal axis of said valve for pressing forcibly said closing element against said seat when said flats on said side projections of said bushing interact with said flats on said body said interaction being effected by means of said two-arm lever turned around the longitudinal axis of said valve after said bushing has completed its free travel towards said seat.

United States Patent [72] Inventors [22] Filed Dec. 23, 1969 [45] Patented Nov. 2, 1971 [32] Priority Feb. 20, 1969 [3 3 U.S.S.R.

[54] VALVE FOR VACUUM INSTALLATION 3 Claims, 5 Drawing Figs.

521' vs. c1 251/296, 251/251 [51] Int. Cl ..F16k 31/00, Fl 6k 31/524 [50] Field otSearch 251/231, 233, 251, 296, 335

[56] References Cited UNITED STATES PATENTS 1,785,766 12/1930 Callaway 1. 251/296 X Primary Examiner-Henry T. Klinksiek Attorney-Waters, Roditi, Schwartz & Nissen ABSTRACT: The invention relates to valves for vacuum installations wherein the closing element is connected with the movable part of the drive which can be fixed in the open" and closed positions and can move freely between these positions.

The claimed drive comprises a bushing having side projections and installed with their aid in linear guides of the valve body for moving in them without turning towards a seat 16 and away from it with the aid of at least one tw0arm lever connected with said bushing and bearing with one end against the body of said valve when the latter is opened. The length of the linear guides is approximately equal to the length of the free travel of said bushing, and the side projections of said bushing and said body of said valve have flats slanted at one and the same acute angle to the longitudinal axis of said valve for pressing forcibly said closing element against said seat when said flats on said side projections of said bushing interact with said flats on said body said interaction being effected by means of said two-arm lever turned around the longitudinal axis of said valve after said bushing has completed its free travel towards said seat.

PATENTEU 2 3,6111 7, 026

SHEET 2 BF 3 I PATENTEDHUVZ ml 3,617. 026

SHEET 30F 3 VALVE FOR VACUUM INSTALLATION The present invention relates to vacuum installations and more specifically its relates to valves for such installations.

Most successfully this valve can be used in the ultrahigh vacuum installations heated for the evacuation of gas, in which the valve operating time is counted by a few seconds.

From the quick-closing valves used up to the present time, the most widespread ones have a stem of the closing element rigidly connected with the handle and provided with a projection moving along a shaped slot in the body. The middle section of said slot is directed along the longitudinal axis of the stern while the end sections are perpendicular to this axis. The end sections of this slot are used to lock the closing element in the open and closed positions while the middle section allows the closing'element to move freely towards the seat or away from it. The tightness of the valve in the closed position is ensured by a nonmetallic sealing ring made of a flexible material. The clearance between the body and stem is sealed by a stuffing box (see, for example A. l. Pipko and others Equipment for evacuation of medium in vacuum installations" Moscow, 1965, p. 90).

However, the use of the known valves of this type in the ultrahigh vacuum installations is hampered by the fact that the drive of these valves presses the closing element against the seat with a force not exceeding -100 kg. which, obviously, is insufficient for producing a requisite tightness. Besides, the sealing of the valve in the closed" position by a nonmetallic sealing ring at relatively high temperatures in heated vacuum installations involves frequent replacements of this ring. The

pressure tightness of the ring is comparatively low and, during the opening of the valve, the gas begins to be liberated intensively and penetrates into the material of this ring.

An object of the present invention resides in eliminating the aforesaid disadvantages.

The main object of the invention consists in providing such a valve for the vacuum installation which, in a relatively short operating time, would press the closing element with a force sufficient for the requisite tightness even without a nonmetallic sealing ring.

This object can be successfully achieved by ensuring the reproducibility of the relative positions of the closing element and seat in the "closed position.

To achieve the aforementioned object we hereby claim a valve for vacuum installations wherein the closing element is connected with the movable part of the drive which can be fixed in the open and closed positions and move freely between these positions. According to the invention, the movable part of the drive of this valve comprises a bushing with side projections, said bushing being installed with the aid of the latter in the linear guides of the valve body for moving along said guides without turning towards the seat and away from it with the aid of at least one two-arm lever connected with the bushing and bearing with one end against the valve body when the valve is being opened, the length of the linear guides being approximately equal to the length of the free travel of the bushing, the side projections of the bushing and the valve body being provided with flats slanting at one and the same acute angle to the longitudinal axis of the valve, for pressing the closing element against the seat owing to the in teraction of the flats on the side projections of the bushing with the flats on the body when the bushing is turned by the two-arm lever around the longitudinal axis of the valve after said bushing has accomplished its free travel towards the seat.

The length of the linear guides is selected as stated above in order to allow the side projections of the bushingto come out of said linear guides so that the flat of the projections at the end of the free travel would be able to interact with the flats of the body.

The slanting angle of the flats on the bushing and valve body is selected so as to withstand the relatively high force applied to the closing element. if the drive is self-locked in the closed" position.

In the preferable embodiment of the claimed valve it is practicable that the valve space be .isolated from the atmosphere by means of a bellows, one end of which is connected to the closing element while the other end is linked with the body. The use of a metal bellows allows the valve to be heated to comparatively high temperatures.

To flx the closing element of the valve in the open" position it is practicable that the two-arm lever be mounted on a bracket, connected rigidly to the bushing and acting additionally as a stop for the lever when the latter is so turned (with the valve open) that is ends interacting with the valve body is located farther from the longitudinal axis of the valve than its opposite end.

A substantial advantage of the present invention consists in that if the valve operation lasts not over a second, the force pressing the closing element against its seat reaches several tons.

Now a preferable embodiment of the valve according to the invention will be described in detail with reference to the accompanying drawings in which:

FIG. 1 is a longitudinal section of a valve for vacuum installations according to the invention, open position;

FIG. 2 shows the closed position of the same,

FIG. 3 is a section taken along line Ill-Ill of FIG. 1;

FIG. 4 is a section taken along line IV-IV of FIG. 1;

FIG. 5 is an enlarged view of the arrangement of flats on the valve drive and body.

The valve for a vacuum installation (not shown in the drawings) comprises a closing element 1 (FIGS. I and 2) connected to one end of the stem 2 by means of a stud 3. The other end of the stem 2 carries a threaded extension 4 on which a bushing 5 is secured by means of a nut 6. The bushing 5 has side projections 7 (FIGS-2 through 5) located in straight slots 8 (FIG. 5) arranged in a flange 9 between projections W. The walls of the projections 10 serve as linear guides for the bushing 5 during its linear motion and keep the bushing against turning relative to the longitudinal axis of the valve. The length of slots 8 is equal to the length of the free travel of the closing element 1 between the open" and closed positions. This allows the projections 7 to come out of the slots 8 upon completion of said free travel. The lower part of the flange 9 is provided with a recess 11 (FIGS. 1, 2 and 5) which allows the bushing 5 to be turned about the longitudinal axis of the valve.

The upper flats 12 (FIG. 5) of the side projections 7 of the bushing 5 and lower flats 13 (FIGS. 4 and 5) of the projections 10 forming slots are inclined to the longitudinal axis of the valve at the angle of 88-89.

As the bushing 5 is turned in the recess 11, the upper flats 12 on the bushing interact with the lower flats 13 on the flange 9.

The flange 9 is connected rigidly with the body 14 by means of four screws 15 (FIG. 3). Located in the lower part of the body 14 is a fixed seat l6 (FIGS. 1 and 2) while an inlet pipe 17 is arranged coaxially with the seat. Located above the pipe 17 in the sidewall of the body 14 is a hole accommodating the outlet pipe 18.

The upper end of the bushing 5 carries a bracket 19 secured by means of splines (not shown) on the bushing and cor responding sockets in the walls of the hole in the bracket 19. Above the splines, the upper end of the bushing 5 has threads interacting with a nut 20 which prevents the bracket 19 from moving along the longitudinal axis of the bushing 5. Mounted on the bracket 19 with the aid of pivots 21 are two two-arm levers 22 whose shorter arms 23 interact with the upper surface 25 of the flange 9 when the longer arms 24 serving as handies are moved.

The inside space of the valve body I4 is isolated from the atmosphere by means of a metal bellows 26 one end of which is welded to the stem 2 while the other end is welded to an insert 27 which is connected tightly with the body 14 by means of a flange 28 and four bolts 29 (two bolts are shown). Installed between the insert 27 and the body 14 is a copper gasket 30.

The bellows 26 is not confined only to the role of an isolating element. Its other function is the flexible loading of the valve drive.

The flange 28 aligns the stem 2 and, consequently, the closing element 1 with relation to the seat 16. The flange 28 has a longitudinal slot 31, in which slides a key 32 secured to the stem 2 and this prevents the stem 2 and the closing element 1 connected to it from turning around the longitudinal axis of the valve.

Since the flanges 9 and 28 are not interconnected, the flange 28 is relieved of the surplus forces imposed by the drive while closing the valve; this improves the pressure tightness of the dismountable joint between the bellows 26 and the body 14.

The closing element 1 of a tapered shape is made of a copper alloy. Other soft metals can be used too. The seat 16 is cylindrical in shape with a rectangular face and is made of stainless steel. Other hard metals can be used too.

It must be understood that the closing device in the described valve, consisting of a seat and a closing element, may be realized differently, provided it meets the operational requirements of the vacuum installations.

All the basic parts and units of the valve, that is the body 14, flanges 9 and 28, bushing 5 and stem 2, are made of stainless steel. If they are heated to +500 C. and above, the permeability of stainless steel to gases rises sharply and its mechanical strength diminishes through microcorrosive damage. To avoid this adverse phenomenon and prevent the jamming and seizure of the friction parts at elevated temperatures, their surface is plated with known heat-resistant, anticorrosion and antifriction coatings, mainly by sulfurization or cadmium plating. Molybdenum disulfide may be used as such a protective coatmg.

The claimed valve functions as follows.

Assume that the initial position of the valve is open" (FIG. 1). To close the valve, the levers 22 are turned to a horizontal position around their pivots 21. The resilient forces produced by the compressed bellows 26 move the bushing 5, stem 2 and closing element 1 down to a certain intermediate position of equilibrium which corresponds to a half-open position of the valve in which it is held by the nonloaded bellows 26 in the absence ofthe axial load on the stem 2 (or in the case of equal pressures on both sides ofthe bellows 26).

While in the neutral position, the levers 22 occupy a horizontal position, perpendicular to the valve axis, and the side projections 7 of the bushing 5 are located in the slots 8 of the linear guides ofthe flange 9.

Then by shifting the levers down to a stop the closing element 1 is brought close to the seat 16. In this position the bellows 26 is stretched and the side projections 7 of the bushing 5 come out of the slots 8 into the recess 11 of the flange 9.

When the levers 22 are turned clockwise around the valve axis through the angle of 15 to 90, the bracket 19 and bushing 5 turn and the upper flats 12 of the projections 7 inclined at 8889 to the longitudinal axis of the valve, start interacting with the lower flats 13 of the projections of the flange 9. The axial force originated during this turn, proportional to the turning angle of the bushing 5, is transmitted by the stem 2 to closing element 1 as a result, the latter is pressed forcibly against the seat 16 thus making the valve pressuretight (FIG. 2).

With the valve in this position, the closing element 1 is fixed in the "closed" position due to the friction forces occasioned in the self-locking screw-and-nut pair formed by the side projections 7 of the bushing 5 and by the projections 10 of the flange 9.

To open the valve, the bracket 19 must be turned by the levers 22 all the way up to the stop counterclockwise around the valve axis. This reduces gradually the force with which the closing element 1 is pressed against its seat 16, the side projections 7 ofthe bushing 5 come out of engagement with the projections 10 and enter the slots 8. The bellows 26 moves the closing element 1 to the middle position of equilibrium which corresponds to the half-open position of the valve.

For further openmg of the valve the levers 22 must be turned around their pivots 2!. The shorter arms 23 of the levers 22 moving over the upper surface 25 of the flange 9 lift the brackets 19 with the bushing 5 and with the associated stem 2 and closing element 1, compressing the bellows 26. The longer arms 24 of the levers 22 come close to each other and bear against the bracket 19 which functions additionally as a stop.

When the two-arm levers 22 come to bear against the bracket 19, the ends of the shorter arms 23 of these levers are located farther from the longitudinal axis of the valve than the ends of their longer arms 24. In this position the levers are pressed by the bellows 26 against the bracket 19 and cannot turn by themselves around the pivots 21; this fixes the bushing 5, stem 2 and closing element 1 in position. In this position of the valve the closing element 1 is fixed in the open" position.

An experimental specimen of the valve realized in compliance with the present invention with a passing capacity of IS l./sec. at a molecular rating, dimensions IX80 and a maximum distance of mm. between the ends of the spread levers has a bore of 30 mm. and weights 3 kg. The free travel is 18 mm. and the time of this travel is 0.5 to 1.0 sec. The travel of the closing element while it is being pressed against its seat is from 0.l to 0.5 mm. which corresponds to a l5-20 turn of the lever bracket and a pressing force of up to 10 tons.

The force required for turning the bracket by the levers is not over 10 kg.

The claimed valve may be fitted with a quick-acting remotecontrolled drive, which would reduce the opening and closing time of the valve.

While a specific embodiment of the invention has been disclosed in the description it will be understood that various modifications and changes within the spirit and the scope of the invention may occur to those skilled in the art.

These changes and modifications can be resorted to without departing from the function or the scope of the invention as hereinafter defined by the appended claims.

We claim:

1. A valve for vacuum installations comprising: a cylindrical body with inlet and outlet pipes; a seat in said body; a closing element interacting with said seat; a bushing with side projections connected with said closing element and moving to said seat and away from it jointly with said element; linear guides in said body located along the longitudinal axis of said valve and interacting with said side projections of said bushing; flats on said projections of said bushing slanted at one and the same acute angle to said longitudinal axis of the valve; flats on said valve body slanted at the same acute angle to the longitudinal axis of the valve as said flats on said projections of said bushing; at least one two-arm lever connected with said bushing and hearing by one end against the body of said valve when the latter is opened; by means of this lever said bushing moves freely without turning in said linear guides towards said seat and away from it, the length of said linear guides being approximately equal to the length of said free travel of said bushing; a recess under said linear guides intended to allow said bushing to come out of these guides at the end of said free travel towards said seat; in this recess said bushing is turned by said two-arm lever for making said flats on said bushing interact with said flats on said body so that said closing element is pressed forcibly against said seat.

2. A valve according to claim 1 wherein the space of said body is isolated from the atmosphere by means of a bellows one end of which is connected to said closing element while its other end is connected to this body.

3. A valve according to claim 2 wherein said two-arm lever is mounted on a bracket connected rigidly with said bushing and serving as a stop for this lever when the latter is so turned (the valve being open) that its end interacting with said valve body is farther from the longitudinal axis of the valve than its opposite end.

III i t t It 

1. A valve for vacuum installations comprising: a cylindrical body with inlet and outlet pipes; a seat in said body; a closing element interacting with said seat; a bushing with side projections connected with said closing element and moving to said seat and away from it jointly with said element; linear guides in said body located along the longitudinal axis of said valve and interacting with said side projections of said bushing; flats on said projections of said bushing slanted at one and the same acute angle to said longitudinal axis of the valve; flats on said valve body slanted at the same acute angle to the longitudinal axis of the valve as said flats on said projections of said bushing; at least one two-arm lever connected with said bushing and bearing by one end against the body of said valve when the latter is opened; by means of this lever said bushing moves freely without turning in said linear guides towards said seat and away from it, the length of said linear guides being approximately equal to the length of said free travel of said bushing; a recess under said linear guides intended to allow said bushing to come out of these guides at the end of said free travel towards said seat; in this recess said bushing is turned by said two-arm lever for making said flats on said bushing interact with said flats on said body so that said closing element is pressed forcibly against said seat.
 2. A valve according to claim 1 wherein the space of said body is isolated from the atmosphere by means of a bellows one end of which is connected to said closing element while its other end is connected to this body.
 3. A valve according to claim 2 wherein said two-arm lever is mounted on a bracket connected rigidly with said bushing and serving as a stop for this lever when the latter is so turned (the valve being open) that its end interacting with said valve body is farther from the longitudinal axis of the valve than its opposite end. 